The Science of Weights in Ancient Sri Lanka: A Study based on Equal Arm Balance from Alahana Pirivena, Polonnaruwa.

Early inscriptions as well as numerous literary sources refer to weight systems prevailed in ancient Sri Lanka. Supplementary to these sources, archeological excavations have revealed the remains of some early stage equal arm balances. The balance located during excavations at Menik Vehera of Alahana Monastic Complex, Polonnaruwa occupies a great importance among them due to its considerably preserved status. Intention of this paper is to link the details of weight systems as stipulated in the early textual sources with a sensitivity analysis on this ancient balance, exploring their correlation. In the mean time, findings of similar equal arm balances and alternative applications of different arm balances are also discussed. Limitations of weight as a measurement parameter and the application of volume for larger quantities such as grain measurements is also discussed, paving the way to identify the salient features of ancient weight system deviating from the present applications.